Skype has abandoned its efforts to avoid complying with an open-source licence that requires it to provide source code with Linux-based VoIP phones.

The company has dropped its appeal against its conviction last July in a German court of failure to comply with the General Public License version 2 (GPLv2). The licence requires vendors to ship source code with any open-source product, but Skype's WSKP100 phone was sold without giving users access to the source code, according to a case brought by gpl-violations.org, a group policing open-source licence violations.

Skype's appeal argued that the GPL licence was not valid in Germany, claiming that GPL breaks the country's antitrust laws. This was thrown out by the appeals court and Skype has abandoned its efforts to overturn the conviction, according to software developer Harald Welte, who runs gpl-violations.org.

"In the end, the court hinted twice that, if it was to judge about the case, Skype would not have very high chances," said Welte in his blog. "After a short break, Skype decided to revoke their appeals case and accept the previous judgement of the lower court as the final judgement."

Skype's appeal made this the most lengthy of a series of cases that Welte has brought against vendors. The court suggested the two parties might "reach an agreement", but Welte is only interested in seeing GPL upheld, precluding that as an option.

While Skype might feel its users don't need access to the source code and are unlikely to use it, the company must abide by the licence requirements, the judges said. If a writer set a condition that his book should only be published in a green cover and there is no other agreement in place, then publishers would have to abide by the green cover — no matter how silly it seems — one of the judges said.

Welte is very definitely aiming to make sure the agreement is followed. "We're not interested in settling for anything less than full GPL compliance," he said.

"To all those who don't like the licence: you don't have to use it; just write your own code. But, if you want to use GPL code, the licence comes with it. It's a package deal," said Pamela Jones of Groklaw.